[PATCH] hid: topre: Fix n-key rollover on Realforce R3S TKL boards

[Daniel Brackenbury <daniel.brackenbury@gmail.com>]

Newer model R3* Topre Realforce keyboards share an issue with their older
R2 cousins where a report descriptor fixup is needed in order for n-key
rollover to work correctly, otherwise only 6-key rollover is available.
This patch adds some new hardware IDs for the R3S 87-key keyboard and
makes amendments to the existing hid-topre driver in order to change the
correct byte in the new model.

Signed-off-by: Daniel Brackenbury <daniel.brackenbury@gmail.com>
---
 drivers/hid/Kconfig     | 3 ++-
 drivers/hid/hid-ids.h   | 1 +
 drivers/hid/hid-topre.c | 7 +++++++
 3 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/hid/Kconfig b/drivers/hid/Kconfig
index b53eb569bd49..8280b5c1e48e 100644
--- a/drivers/hid/Kconfig
+++ b/drivers/hid/Kconfig
@@ -1167,7 +1167,8 @@ config HID_TOPRE
 	tristate "Topre REALFORCE keyboards"
 	depends on HID
 	help
-	  Say Y for N-key rollover support on Topre REALFORCE R2 108/87 key keyboards.
+	  Say Y for N-key rollover support on Topre REALFORCE R2 108/87 key and
+          Topre REALFORCE R3S 87 key keyboards.
 
 config HID_THINGM
 	tristate "ThingM blink(1) USB RGB LED"
diff --git a/drivers/hid/hid-ids.h b/drivers/hid/hid-ids.h
index c448de53bf91..a0fc6fa27004 100644
--- a/drivers/hid/hid-ids.h
+++ b/drivers/hid/hid-ids.h
@@ -1301,6 +1301,7 @@
 #define USB_VENDOR_ID_TOPRE			0x0853
 #define USB_DEVICE_ID_TOPRE_REALFORCE_R2_108			0x0148
 #define USB_DEVICE_ID_TOPRE_REALFORCE_R2_87			0x0146
+#define USB_DEVICE_ID_TOPRE_REALFORCE_R3S_87			0x0313
 
 #define USB_VENDOR_ID_TOPSEED		0x0766
 #define USB_DEVICE_ID_TOPSEED_CYBERLINK	0x0204
diff --git a/drivers/hid/hid-topre.c b/drivers/hid/hid-topre.c
index 848361f6225d..ccedf8721722 100644
--- a/drivers/hid/hid-topre.c
+++ b/drivers/hid/hid-topre.c
@@ -29,6 +29,11 @@ static const __u8 *topre_report_fixup(struct hid_device *hdev, __u8 *rdesc,
 		hid_info(hdev,
 			"fixing up Topre REALFORCE keyboard report descriptor\n");
 		rdesc[72] = 0x02;
+	} else if (*rsize >= 106 && rdesc[28] == 0x29 && rdesc[29] == 0xe7 &&
+				    rdesc[30] == 0x81 && rdesc[31] == 0x00) {
+		hid_info(hdev,
+			"fixing up Topre REALFORCE keyboard report descriptor\n");
+		rdesc[31] = 0x02;
 	}
 	return rdesc;
 }
@@ -38,6 +43,8 @@ static const struct hid_device_id topre_id_table[] = {
 			 USB_DEVICE_ID_TOPRE_REALFORCE_R2_108) },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_TOPRE,
 			 USB_DEVICE_ID_TOPRE_REALFORCE_R2_87) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_TOPRE,
+			 USB_DEVICE_ID_TOPRE_REALFORCE_R3S_87) },
 	{ }
 };
 MODULE_DEVICE_TABLE(hid, topre_id_table);
-- 
2.48.1